Water-based coating compositions

Abstract

Water-based coating compositions comprise a water-dilutable polyurethane hybrid binder, obtained by polymerization of a polyurethane macromonomer, containing a lateral and/or terminal vinyl group, in the presence of an unsaturated monomer copolymerizable with the polyurethane macromonomer, optionally a curing agent, and a pigment. The polyurethane macromonomer is based on a polyhydroxyl compound. The polyhydroxyl compound comprises at least about 50% by weight of a polycarbonate polyol, which is liquid at 20° C., the % by weight based on the total amount of the polyhydroxyl compound.

1 . A water-based coating composition comprising;
 a water-dilutable polyurethane hybrid binder, obtained by polymerization of a polyurethane macromonomer, containing a lateral and/or terminal vinyl group, in the presence of an unsaturated monomer copolymerizable with the polyurethane macromonomer;   optionally a curing agent; and   a pigment,   wherein the polyurethane macromonomer is based on a polyhydroxyl compound, the polyhydroxyl compound comprising at least about 50% by weight of a polycarbonate polyol, which is liquid at 20° C., the % by weight based on the total amount of the polyhydroxyl compound.   
     
     
         2 . The water-based coating composition of  claim 1 , wherein the polyurethane macromonomer is obtained by reacting components comprising:
 a polyisocyanate;   a polyhydroxyl compound, the polyhydroxyl compound comprising at least about 50% by weight of a polycarbonate polyol, which is liquid at 20° C., the % by weight based on the total amount of the polyhydroxyl compound;   a compound containing a functional group reactive towards isocyanate groups and a group chosen from ionic groups, groups capable of forming ions and non-ionic hydrophilic groups; and   a compound containing a vinyl group and a hydroxyl group.   
     
     
         3 . The water-based coating composition of  claim 1 , wherein the water-dilutable polyurethane hybrid binder comprises at least about 100 milliequivalents of carbonate groups (per 100 g polyurethane binder solids). 
     
     
         4 . The water-based coating composition of  claim 3 , wherein the water-dilutable polyurethane hybrid binder comprises at least about 100 milliequivalents of carbonate groups (per 100 g polyurethane binder solids) and at least about 100 milliequivalents of urethane and urea groups (per 100 g polyurethane binder solids). 
     
     
         5 . The water-based coating composition of  claim 1 , wherein the water-dilutable polyurethane hybrid binder has a hydroxyl value of 0 to about 150 mg KOH/g and an acid value of about 15 to about 50. 
     
     
         6 . The water-based coating composition of  claim 1 , wherein the polyhydroxyl compound comprises about 60 to about 100% by weight of the polycarbonate polyol, which is liquid at 20° C., the % by weight relative to the total amount of polyhydroxyl compound. 
     
     
         7 . The water-based coating composition of  claim 1 , wherein the at least one polycarbonate polyol, which is liquid at 20° C., has a number average molecular weight Mn of 300-5000. 
     
     
         8 . The water-based coating composition of  claim 1 , wherein the polycarbonate polyol which is liquid at 20° C. is based on a combination of 1,3-propanediol and 1,5-pentandiol, on a combination of 1,3-propanediol and 1,4-butandiol, on a combination of 1,4-butandiol and 1,6-hexanediol and/or on a combination of 1,5-pentandiol and 1,6-hexanediol. 
     
     
         9 . The water-based coating composition of  claim 1 , wherein the polycarbonate polyol which is liquid at 20° C. is based on a combination of 1,5-pentandiol and 1,6-hexanediol and/or a combination of 1,3-propranediol and 1,4-butanediol. 
     
     
         10 . The water-based coating composition of  claim 8 , wherein the molar ratio of the two diols in each combination is in the range of about 3:1 to about 1:3. 
     
     
         11 . The water-based coating composition of  claim 1 , wherein the pigment comprises an effect pigment. 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . The water-based coating composition of  claim 9 , wherein the molar ratio of the two diols in each combination is in the range of about 3:1 to about 1:3.